Strain-balanced InAs/InAs1−xSbx type-II superlattices grown by molecular beam epitaxy on GaSb substrates

Abstract

Strain-balanced InAs/InAs1−xSbx type-II superlattices (SLs) on GaSb substrates with 0.27 ≤ x ≤0.33 were grown by molecular beam epitaxy and demonstrated photoluminescence (PL) up to 11.1 μm. The calculated SL bandgap energies agree with the PL peaks to within 5 meV for long-wavelength infrared samples (9.5, 9.9, and 11.1 μm) and to within 9 meV for a mid-wavelength infrared sample (5.9 μm). X-ray diffraction measurements reveal average SL mismatches of less than 0.2%, and the PL full-width-at-half-maximums increase with the mismatch, confirming the importance of strain-balancing for material quality.